Patent GB-1077205-A (GB)
Title: Improvements in or relating to electromechanical transducers
IPC: H04R23/00
Filed: 1965-09-08
Abstract: 1,077,205. Semi-conductor transducers. SIEMENS A.G. Sept. 8, 1965 [Sept. 9, 1964], No. 38287/65. Heading H4J. A microphone or other transducer includes a semi-conductor junction on which pressure is exerted by mechanical movement to produce electrical variations. The pressure is exerted through a coupling arrangement by means of which forces can be transmitted only if they are below a predetermined magnitude less than the breaking point of the arrangement. Spring couplings.-A transducer (Fig. 1) comprises a support 1, a diaphragm 2 and a sheet-metal housing 3, 4, 5. An insert 7 carries a semi-conductor junction 8. Secured to the support 1 is a leaf spring 10 which carries a sapphire needle 11 serving as a pressure member. A diaphragm pin 13 is fastened to the diaphragm 2 and is contacted by the bent portion 12 of the spring 10 and by a second spring 14. The spring 14 can be adjusted by a screw 15. Alternatively (Figs. 4, 5, not shown), a single spring (41) fastened at both ends may replace the two springs 10, 14. The spring (41) has a central aperture (42) with two resilient lobes (44, 45) which press against a diaphragm pin (43). The spring (41) carries a sapphire needle (46). In another arrangement (Fig. 2, not shown) a diaphragm pin (28) is hinged to a diaphragm 11 and two opposed springs (26, 30) bear against it. Spring (26) carries a sapphire needle (27) whose axis is perpendicular to the diaphragm pin (28). Magnetic couplings.-The lower end (39) (Fig. 3, not shown) of a diaphragm pin (38) is a permanent magnet and a leaf spring (36) carrying a sapphire needle (35) is of magnetically conducting material. In this arrangement the end (39) of the pin (38) is held against one end of the spring (36) by magnetic attraction. Alternatively (Fig. 6, not shown), a leaf spring (48) carrying a sapphire needle (51) is held at both ends and has a central perforation (49). The spring (48) is of magnetically conducting material and the lower end of a diaphragm pin (50) is a permanent magnet and bears against one edge of the perforation (49). In a modification (Fig. 10, not shown) the lower end of a diaphragm pin (75) is of magnetically conducting material and is urged against one edge of a central perforation (76) in a leaf spring (70) by an adjustable permanent magnet (77). A sapphire needle (57) (Fig. 8, not shown) may be attached to a rigid but hinged support (58) and have its axis perpendicular to a diaphragm pin (61). The diaphragm pin (61) is a permanent magnet and the support (58) is of magnetically conducting material whereby the pin (61) is pressed against the support (58). Alternatively, a diaphragm pin (67) (Fig. 9, not shown) is of magnetically conducting material and is urged against a support (65) carrying a sapphire needle by a permanent magnet (68) secured to an insert (62) to which is also secured a semi-conductor junction (63). In a further embodiment (Fig. 11, not shown), a leaf spring (91) of magnetically conducting material carries a sapphire needle (93) and, between the spring (91) and a diaphragm pin (95), also of magnetically conductive material, is a permanent magnet (96). Diaphragm.-The diaphragm (85) (Fig. 12, not shown) is provided with an indentation (86) having a central opening (89). A pin (87) passes through the opening (89) and has a spherical head (88) which is pressed into the indentation (86) by a leaf spring (90). A ball-and-socket type joint is thereby obtained.